Double tubes of the above-described type, as well as other types of two-chamber or multi-chamber tubes are used, for example, for packing different types of products or components which, on mutual contact, react easily with one another, either chemically or in some other way. It is desirable that such reaction occurs only in connection with the contents, in portions or completely, being emptied from the tube. Under such conditions, the components therefore have to be stored separately in the tube.
Applications other than that mentioned above also exist. A double tube or other multi-chamber tube can be used, for example, to deliver “striped toothpaste”.
U.S. Pat. No. 1,676,734 discloses an early approach of sequentially filling inner- and outer tubes of a double tube.
For rapid and reliable processing of such double tubes, however, an effective filling step and thus a commercially competitive tube-filling machine are lacking at present.
Such a tube-filling machine is to be capable of being used, with precision and high capacity, for producing defect-free, filled tubes without operational stoppages of the machine as a consequence of, for example, contamination in connection with filling, poor sealing of filled tubes or other hitches which disrupt functioning.
In order to achieve high output capacity, it is also to be possible when necessary for the filling, to carry out the filling in a parallel manner with a large number of tubes simultaneously in the filling station.
Double tubes of the type mentioned above have previously caused major problems, and it has not been possible to effectively fill such tubes in tube-filling machines without encountering the disruptions mentioned above.
One object of the present invention is to therefore eliminate this disadvantage and to provide an effective filling process and a tube-filling machine for the double tubes.